Complex and large electric circuit networks such as systems control networks for power stations and nuclear reactors are typically broken down into a plurality of small circuits each mounted on a modular printed circuit board. The printed circuit boards, which are electrically interconnected to make up the network, enable fast and easy replacement of failed network components as well as providing flexibility of design.
Printed circuit boards are typically rectangular and are mounted vertically in racks. Generally, the top and bottom edges of the boards slide in tracks and the back edge is equipped with some electrical connector means.
The front of the printed circuit board module is equipped with a plate for handling, identification and esthetic purposes. Also some mechanism is typically provided to lock the circuit board module to the circuit board rack. This is desired to prevent withdrawal of the module and thereby breaking of the circuit network in the event of some withdrawal force being applied to the circuit board by accident.
Known racks for retaining such printed circuit board modules were usually trays made from a series of various custom parts, were not reversible and were expensive to manufacture.